Can you make a mesh follow another mesh with Cloth Sim?
What you can do is to link the pinned of the vertices and the rigid body to a bone. 

Create a bone and apply the metarig to the cloth with empty groups first.


After this, delete the Bone vertice group and copy its name to the name of the pinned group.



Now parent the bone to the rigid body(select the bone first).

And there you go.